At the bottom of the same chart, you can also compare with /u/_supert_'s price prediction model which is based on tx growth. Notice the model has a major divergence during the period where the Gox thieves would be unloading 100s of thousands of coins, but then it settles back into it's original growth slope.
Conclusion: The mega bubble was driven by fraudulent/inorganic activity and we should not expect a repeat. However, fundamentals are strong and adoption continues to grow. It may be wise to take a multi-year outlook.
I believe we're still low on the S-curve of technology adoption, and thus there's no reason to believe that we will cease exponential growth yet. See "Speculative Adoption Theory" for a great read.
Near term, we could go as low as 1600 while remaining . Long term, we should see $50k or even $100k coins by the end of 2020.